src/popup.html

<!DOCTYPE html>
<head>
    <script type="text/javascript" src="../build/popup.js"></script>

    <style>
        .container {
            width: 300px;
        }

        .flex-container {
            display: flex;
        }

        .flex-item-1 {
            flex: 1;
        }

        .flex-item-4 {
            flex: 4;
        }

        .logo {
            padding-right: 15px;
        }

        .title {
            font-size: 15px;
            font-weight: lighter;
        }

        .info {
            padding-top: 5px;
        }

        .website {
            text-decoration: none;
            color: #404f6b;
        }

        .website:hover {
            color: #020406;
        }

        .version {
            padding-top: 1px;
        }

        .lib {
            padding: 7px 0;
        }

        .lib:not(:last-child) {
            border-bottom: 1px solid #f1eeee;
        }

        .message {
            text-align: center;
            font-size: 16px;
        }

        .try-again {
            color: #404f6b;
            cursor: pointer;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="message"></div>
    </div>
</body>
</html>